From 8f0f9eb4d059480d712ea7982cf0f7b91ff06790 Mon Sep 17 00:00:00 2001
From: Ray Speth <speth@mit.edu>
Date: Sat, 30 May 2026 13:14:07 -0400
Subject: [PATCH 1/2] [SCons] Allow CC/CXX/AR/FC env variables for compiler
 selection

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 SConstruct | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/SConstruct b/SConstruct
index b51e22a409..b6f8e1e844 100644
--- a/SConstruct
+++ b/SConstruct
@@ -313,11 +313,11 @@ config_options = [
     Option(
         "AR",
         "The archiver to use.",
-        "${AR}"),
+        os.environ.get("AR") or "${AR}"),
     Option(
         "CXX",
         "The C++ compiler to use.",
-        "${CXX}"),
+        os.environ.get("CXX") or "${CXX}"),
     Option(
         "cxx_flags",
         """Compiler flags passed to the C++ compiler only. Separate multiple
@@ -330,7 +330,7 @@ config_options = [
     Option(
         "CC",
         "The C compiler to use. This is only used to compile CVODE.",
-        "${CC}"),
+        os.environ.get("CC") or "${CC}"),
     Option(
         "cc_flags",
         """Compiler flags passed to both the C and C++ compilers, regardless of
@@ -397,10 +397,11 @@ config_options = [
         "default", ("y", "n", "default")),
     PathOption(
         "FORTRAN",
-        """The Fortran (90) compiler. If unspecified, the builder will look for a
-           compatible compiler (pgfortran, gfortran, ifort, ifx, g95) in the 'PATH'
-           environment variable. Used only for compiling the Fortran 90 interface.""",
-        "", PathVariable.PathAccept),
+        """The Fortran (90) compiler. If unspecified, the 'FC' environment variable is
+           used if set; otherwise the builder will look for a compatible compiler
+           (pgfortran, gfortran, ifort, ifx, g95) in the 'PATH' environment variable.
+           Used only for compiling the Fortran 90 interface.""",
+        os.environ.get("FC") or "", PathVariable.PathAccept),
     Option(
         "FORTRANFLAGS",
         "Compilation options for the Fortran (90) compiler.",

From ab2ce49cba8dd370c01651b97ea236deac7df639 Mon Sep 17 00:00:00 2001
From: Ray Speth <speth@mit.edu>
Date: Sat, 30 May 2026 13:18:55 -0400
Subject: [PATCH 2/2] Use correct compiler toolchain package in Linux Pixi
 environments

These packages provide a complete toolchain and set the CC/CXX/AR
environment variables (which SCons now looks for), allowing for a
consistent compiler environment whether or not system compilers are
present.

Fixes #2118.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 pixi.toml | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pixi.toml b/pixi.toml
index 60cc10dfc7..4cf47d0f62 100644
--- a/pixi.toml
+++ b/pixi.toml
@@ -31,8 +31,14 @@ pytest = ">=9.0.2,<10"
 "ruamel.yaml" = ">=0.19.1,<0.20"
 jinja2 = ">=3.1.6,<4"
 
+# Provide a self-consistent compiler toolchain matching the conda-forge-built
+# dependencies. The activation packages set CC/CXX/AR, which SConstruct honors. To build
+# with the system compiler instead, set `CXX = "g++"` and `CC = "gcc"` in cantera.conf.
 [feature.core.target.linux-64.dependencies]
-clangxx = ">=18.0"
+gxx_linux-64 = ">=13"
+
+[feature.core.target.linux-aarch64.dependencies]
+gxx_linux-aarch64 = ">=13"
 
 [feature.samples.dependencies]
 pandas = ">=3.0.0,<4"